nathan



Aug. 11, 1959 M. F. NATHAN 2,

FLUID PLATINUM SYSTEM Original Filed Feb. 16, 1954 STRIPPER /53 I62 I64 I 75 I76 TOTAL i 43 VAPOR STRIPPER =1 l7 m FRACTIONATOR\ |4o I Is? -l33 I68 DEAERATEO NAPHTHA 5 FEED INV'ENTOR M. F. NATHAN BY 6. H. PALMER ATTORNEY c. 0. FARNSWORTH AGENT United States Patent FLUID PLATINUM SYSTEM Marvin F. Nathan, New York, N.Y., assignor to The M. W. Kellogg Company, Jersey City, N..l., a corporation of Delaware Original application February 16, 1954, Serial No. 410,571, new Patent No. 2,791,542, dated May '7, 1957. Divided and this application July 9, 1956, Serial No. 596,721

8 Claims. (Cl. 23-288) This invention relates to improved method and means of effecting the conversion of hydrocarbons and, more particularly, it pertains to improved method and means of effecting the conversion of light hydrocarbon oils to normally liquid material of high anti-knock quality by means of a fluidized platinum catalyst. Still more particularly, this invention is concerned with an improved method of stripping spent or contaminated catalyst which is employed in the hydrocarbon conversion zone, and further, it provides an effective method for minimizing catalyst loss due to entrainment in the gaseous efiiuent streams from the processing zones.

This application is a division of application Serial No. 410,571, filed February 16, 1954, now US. Patent 2,- 791,542.

In the field of hydroforming, the fluid technique has been applied principally to a type of catalyst which is relatively cheap, hence, the operation can tolerate catalyst loss due to entrainment in the gaseous effluent streams. Since platinum catalysts are quite expensive to manufacture, it was not advisable in the past to employ the same in a fluid system by reason that the high catalyst loss makes this practice prohibitive. However, in accordance with the present invention, method and means are provided whereby a platinum catalyst can be employed in a fluid system without incurring substantial or significant 108s of catalyst due to entrainment in the gaseous efiiuent streams of the processing zones.

An object of this invention is to provide improved method and means for effecting the conversion of hydrocarbons by means of fluidized platinum catalyst.

Another object of this invention is to provide improved method and means for reforming light hydrocarbon oils by means of fluidized platinum catalyst without incurring substantial loss of catalyst due to entrainment in the gaseous effiuent streams of the processing zones.

Still another object of this invention is to provide an improved method of stripping spent finely divided platinum catalyst which has been employed for the conversion of hydrocarbons, more particularly, to reform light hydrocarbon oils.

Other objects and advantages of this invention will become apparent from the following description and explanation thereof.

It is contemplated by means of the present invention to contact a hydrocarbon reactant with a fluidized mass of finely divided platinum catalyst under suitable conversion conditions in a reaction zone such that a desired reaction product is produced and the catalyst is contaminated with carbonaceous material, withdrawing contaminated catalyst from the reaction zone and passing the same to a first stripping zone wherein it is contacted with a gasiform stripping agent for the removal of volatile material therefrom, passing the stripped catalyst to a second stripping zone wherein it is contacted with a mixture comprising flue gas and hydrogen containing gas for the additional removal of volatile material therefrom, passing the stripped catalyst from the second stripping zone to a first regeneration zone wherein the carbonaceous ma terial on the catalyst is burned with an oxygen containing gas thus producing a flue gas, passing the flue gas from the first regeneration zone to the second stripping zone, passing the regenerated catalyst from the first regeneration zone to a second regeneration zone wherein it is contacted with an oxygen containing gas for rejuvenation treatment, passing the gaseous product material from the second regeneration zone to the first regeneration zone, passing catalyst from the second regeneration zone to a reduction zone wherein the catalyst is treated with a gaseous reducing material, passing the gaseous efiiuent from the second stripping zone and the reducing zone to the reaction zone, passing catalyst from the reducing zone to the reaction zone, and introducing hydrogen containing gas to the second stripping zone in an amount sufficient to react with all of the oxygen being supplied to the first and second regeneration zones.

The present invention is applicable to a hydrocarbon conversion process in which platinum is useful as a catalytic material. For example, the present invention can be used for reforming, desulfurization, hydrodesulfurization, hydrogenation, dehydrogenation, hydrocracking, isomerization, etc. Among the various uses of the pressent invention, it is especially suited for reforming light hydrocarbon oils. In the case of a hydrocarbon conversion process, a suitable hydrocarbon reactant is contacted at a temperature of about 500 to about 1250 F., a pressure of about 1 atmosphere to about 1500 p.s.i.g., a weight space velocity of about 0.05 to about 15, and a catalyst to oil ratio, on a weight basis, of about .01 to about 12.

The reforming of light hydrocarbon oils can be eifected at a temperature of about 750 to about 1150 F., more usually, about 850 to about 975 F. At these temperatures, the total pressure of reaction is maintained at about 50 to about 1000 p.s.i.g., although more usually, the pressure falls within the range of about to about 750 p.s.i.g. The weight space velocity or the quantity of oil processed to the reforming zone, on an hourly basis, relative to the quantity of catalyst present therein is generally about 0.01 to about 10, more usually, about 0.1 to about 5. The quantity of hydrogen which is added to the process is measured in terms of standard cubic feet (70 F. and 760 mm.) per barrel of oil feed (1 barrel equals 42 gallons). In general, the hydrogen feed to the reforming zone can be from about 500 to about 15,000 s.c.f.b., although more usually, it is about 1000 to about 7500 -s.c.f.b The conditions of operation can be selected to provide a reaction involving a net consumption or net production of hydrogen. For the purpose of this invention, it is preferred to operate a reforming reaction to obtain a net production of hydrogen.

The catalyst which is employed for the purpose of this invention comprises platinum. Generally, the platinum catalyst is dispersed on a suitable carrier material such as, for example, alumina, silica-alumina, kieselguhr, pumice, zinc spinel, bauxite, etc. The platinum catalyst can be prepared by any method provided it possesses activity for the reactions intended hereunder. The total catalyst contains about .01 to about 5% by weight of platinum. An excellent catalyst for reforming light hydrocarbon oils is platinum supported on alumina.

In order to provide a better understanding of the present invention, reference will be had to the accompanying drawing which provides part of this specification.

In the drawing, naphtha having an API gravity of 5 82 is supplied from line 5, at the rate of 9000 b.p.s.di, to coil 7 of furnace 9. Naphtha vapors are discharged from furnace 9 by means of line 10 at a temperature of 900 F. and a pressure of 215 p.s.i.g. Recycle gas containing hydrogen is supplied from line 12 at a temperature of 1050 F. and at a rate of 14,443 pounds per hour. Ihe recycle .gas .has a molecular weight of 7.3. The recycle gas in line '12 combines with naphtha vapors in Jinefllland as,a.combined stream they flow through line 14,such that about .20,'000,pounds perjhour of the .miX- ture flows to .line 15 and the remainingportion, that is, 91,883 pounds ,perhour, flows throughline '17. The mixture of recycle gas and naphtha 'flows'to a reforming reactor whichis comprised of a heating section 19, a main reaction section 20and a disengaging section'121. The reactant stream passing throughline 15 enters the'bottom of mixingtconduit 22. Mixing conduit'22'has superimposed upon it an enlarged section '23, which is in turn, connected to heating section "19. 'Regenerated platinum catalyst is introduce'diin'to enlarged section 23 by means of transfer line 25. ;Platinum catalystcontaining 0.6% by weight of platinum .on: alumina is withdrawn from the {upper part of reaction section '20, and it is circulated :downwardly through 'standpipe'27 which contains valve 28 for the purpose of controlling automatically the flow of catalyst therein, and the bottom end of this standpipe is 'connected to mixing .coriduit.22. Fresh'or regenerated platinum catalyst, recycle catalyst andthe mixture of recycle gas and naphtha "flow upwardly throughheating "section 19. Heating'section19 comprises a bank of tubes represented as tubes 29. A'heating medium is supplied to'theshell'side of'heating section '19 by means of inlet 'line 31 which is 'connected 'to the 'bottom end thereof warid this 'heating medium is discharged there from by "means of line 32. In this "example; theheatingmedium is-flue "gashavinga-temperature of 1900" F. and it is discharged from 'heating section 19through -line 32 at *atemperature of'l200" F. A mercury boiler system can -also'be employed-forthepurpose of supplying heat to the reaction zone. In this connection, the mercury is "heated to a'temperature'of-about 1000 to about 1200 under *a-pressure of aboutlOO'to about 300 p.s.i.g. Under these conditions, the mercury is-inthe form of a 'vapor an'das' such, it-is--supplied to heater section 19 by means ofline 32,--wherein it-iscondensed and the heat *of condensation is transferred indirectly to the reform ing zone.

Since hydro'formingwith a platinum catalyst is highly endothermic, heatis prefer-ably supplied to the reaction *zonebymeans-otherthan theuse of a-high catalyst-to 'oil-ratio. T-he combined catalyst-streams of regenerated catalyst-and recycle catalyst are passed upwardly as'a -'-suspensionin the reactant materialthrough heating-section 19 and the-total rnass is heated -while reforming. reactionsare taking-place. The-suspension of catalystin the-reactant material passes from heating section19 to reaction section 20 whereina-dense fluid bed of platinum catalyst is maintainedhavinga level 34. As the catalyst movesupwardlygthrough dense bed '35, the temperature Sis l lowered *by:reason ofcthe; endothermic 'reactions,-.con-

sequently, a portionithereof iswwithdrawnfi'om the top IPaI't'TOfJdCHSObBd. 3Seby meansofline- 27. 'For the pur- ..:.pose of this invention, the recycle catalyst flowing through ystandpipe :27 can :beexpressed .in. terms of a-wcightra- Jtio relative to the quantity of freshly regenerated catalyst Twhich' is supplied to. the reactionsystem via transfer line i111 "general, the'recycle rate .expressedas a weight .ratio of used catalyst-flowing through standpipe, to regenerated catalyst flowing in transfer line .25 is about .l0,000 to about 10:1, more usually, about 50001toabout 50:1. Therefore, by means. ofheating section 19, about 50..to.about 150% of the required endothermic heat ofre- .,action is supplied.

The mixture of naphtha and hydrogen containing, gas :stream is split for passagethrough lines-1S and 17, be-

cause it is desired that aportion ofthe. reactant material, .namely,.the.material flowingin line 15,.serves as the warriengasfor recyclerandlfreshly regenerated catalyst.

The portion of reactant material "flowing in1ine17is introduced directly into the bottom part of catalyst bed 35 in the reaction section 20.

Spent platinum catalyst having a carbon content of about 0.02 to about 1.0% by weight, e.g., 0.2% by weight, is withdrawn from the bottom part of bed 35 by means of recycle gas which is supplied at the rate of 218 pounds per hour through line 38, and the suspension of catalyst in the recycle gas is carried upwardly in a vertical riser :40 which has-its upper end terminating instripping es- -sel 41. Stripping .vesselA-Lis superimposed on disengaging zone 21. As in the case of heating section 519,.rcaction section 20 and-disengaging section 21, the stripper 41 is a vertical, cylindrical vessel. Stripping vessel 41is separated fromdisengaging zone .21 bylmeans ofapartition 43 which slants downwardly to a vertical;partition 45 and this vertical partition is in turn connected to another slanting partition-46. A dense, fluidized bed of platinum catalyst is maintained within part of the stripping vessel and it has a'level 47. 'Recycle-gas containiug hydrogen serves 'asthe gasiform-stripping agent in the stripping-vessel 41,-andit is supplied by-means of line 48 which-is connected to partition'46located in.the'bottom of the stripper. A-second vertical riser 50interconnects disengaging zone 51 of thestripper with the catalyst bed 35 in the-reactor. 'This'riser-serves to -control:thc

level'of catalyst in-the-stripper. -In-the event that the catalyst in'the stripper rises above'the upper end of riser "50,-catalyst -fiows downwardly into reactor'bed 35. -All of the-gaseous-efiluent materialin disengaging zone 51 of the stripper is discharged therefrom bymeans ofa drawn from reactor bed '35 and passed to stripper .41.

While it is'mentionedthat recycle gas is used for-the purpose of stripping in this i illustration, it should be. un-

derstood that in some-instances it may bedesirablezto employ'a different-gasiform:stripping agentsuch as, for example,-steam,nitrogen,: etc. vFurther, the temperature of stripping in stripper 41.can:be .varied from about 450 to about 1000tF. In disengaging zone 51, the

pressure is maintained at.l90'.1 p.s.i.g.

Stripped catalyst :is withdrawn from stripper 41 ,by means of transfer linc"57l havinga bend. 58 in the; middle --portion thereof. The.stripped catalyst'flows from trans- ;fer'line 57-toa secondstripper 60. .The.catalyst is then subjected to a series: of treatments for the'purposev of regeneration. The regeneration system is comprisedofa unitary vesselseparated into four zones and-each. zone issuperimposed -by the other. :The second stripper 60 superimposes a first=regenerator :61, the 'firstzregenator superimposes asecond regenerator 62, whilethe second regenator superimposes a reducer 63. A dense, fluidized -bedof platinum catalyst having a level 66 is maintained '--in second strippcr 60. 1 Recycle gas is introduced into'the bottom of stripper 60 by means of line 68 at the rate of 41'.6 pounds per hour. All ofthe flue gas generated in 'regenerator: 61 is: discharged therefromby means of line 69, and-this'flue-gastis combined-with recycle gas and as a single stream'mayenter the bottom of stripper 60 by means of line 71. It is significant to note that the quantity'of'recycle gasWhich'is -fed to stripper '60 is regulated 'on theibasis that -it will'react with substantially 7 ,all of the oxygen-which is supplied to regenerators 61 'and 62. The -quantityef recycle gas'which is'fedto stripper60, is measured to react with all the oxygen on a 'stoichiometric basis, and-thus it provides a safety measure against the "dangeror; risk of any or all 'the oxygen flowing through the regeneration system 1 without reacting with the carbonaceous material contained on the catalyst. Hence, the flue gas flowing from stripper 60 via line 73 is substantially free of oxygen prior to entering disengaging zone 55 of the reaction system. Further, the flue gas serves to dilute the hydrogen and hydrocarbon material in the recycle gas and, hence, the efliciency of stripping is improved, because the stripping agent in the first stripper 41 is only recycle gas. The second stripper serves an important function in maintaining the total amount of combustible material passing to the first regenerator 61 to a minimum. The combustible material entering the first regenerator 61 is converted to flue gas, and this flue gas will serve to increase the ratio of flue gas to hydrogen evolved by the system, and consequently, it is desirable to strip the spent catalyst as effectively as possible. The quantity of recycle gas introduced into the second stripper 60 is relatively small in comparison with the quantity of flue gas being supplied from the first regenerator. The temperature in stripper 60 is maintained at 700 F. This temperature is selected on the basis that the reaction of recycle gas with all of the oxygen being supplied to the first and second regenerators can only raise the temperature to 1050 R, which is a safe limit for the catalyst without changing the cooling system controls. The increased cooling duty performed by the coils due to the increase in temperature difference between the catalyst bed and the coils compensates for the additional duty resulting from combustion of recycle gas with oxygen. The features described above apply in the case of a cooling involving a vaporizable medium at essentially constant temperature, e.g., water, etc. In the event that reaction conditions are varied such that less coke is produced and so less oxygen is required for regeneration, the temperature of 700 F. can be raised without taking a risk that the catalyst temperature will exceed the upper limit of 1050 F. if all of the oxygen is reacted with the recycle gas. Consequently, the temperature in stripper 60 can be varied from about 600 to about 1100 F. and the upper temperature for the catalyst in this zone while specified as 1050 F., it can be as high as 1150 F.

The temperature of the catalyst in stripper 60 is regulated by means of cooling tubes 75. The pressure in the upper part of stripper 60 is 190.1 p.s.i.g. Stripper 60 is separated from first regenerator 61 by means of a partition 77. Stripped catalyst from stripper 60 is discharged therefrom by means of standpipe 78 which has a slide valve 79 connected to the bottom end thereof. The stripped catalyst flows downwardly through standpipe 78 and forms a dense bed 81 having a level 82 in the first regenerator 61. Air is normally introduced into the bottom part of regenerator 61 by means of line 84 only during start-up. Air and the small amount of products of combustion produced in regenerator 62 is discharged therefrom by means of line 85, hence, the air in line 85 enters the bottom of regenerator 61 by means of line 86. In regenerator 61, the temperature is maintained at about 1050 F. and at a pressure of 195.8 p.s.i.g. Under the conditions existing therein substantially all of the carbonaceous content of the catalyst is removed by burning. The temperature of regeneration in vessel 61 is regulated by means of vertical cooling tubes 89. The temperature of regeneration can be varied over a wide range, namely, from about 600 to about 1100 F. However, it is preferred to maintain the temperature not higher than about 1050 F. in order to avoid substantially deactivating the catalyst at higher temperatures.

It has been found that the properties of a freshly regenerated catalyst which has been treated under relatively mild regeneration conditions can be improved significantly by a severe or drastic treatment involving the proper selection of temperature, oxygen partial pressure and time. For the purpose of this specification and the appended claims, the severe or drastic treatment is known as rejuvenation. The rejuvenation treatment of a platinum catalyst elfects improvements in its activity or. selectivity. The action of this treatment is not completely understood, however, it is known that unusually goodresults are obtained thereby. In general, the rejuvenation treatment involves a temperature of about 700 to about 1200 F., more usually, about 750 to about 1000 F. The catalyst is treated at these temperatures with an oxygen containing gas having an oxygen partial pressure under the conditions of treatment of about 3.5 to about 400 p.s.i.a., more usually, about 5 to about 200 p.s.i.a., and preferably, about 14.7 to about 100 p.s.i.a. The time of treatment varies considerably, because when using a high oxygen partial pressure, the period of treatment can be relatively short and the use of a high temperature may only require a short period of treatment. Conversely, a low temperature and an oxygen containing gas having a low oxygen partial pressure require relatively longer periods of treatment. In general, theperiod of treatment varies from about 15 minutes to about 100 hours, more usually, about 0.5 to about 30 hours. Regenerator 61 is separated from the second regenerator 62 by means of a partition 92. The regenerated catalyst is withdrawn from regenerator 61 by means of a standpipe 93 which has a slide valve 94 at the end thereof for the purpose of controlling the rate of withdrawal. The regenerated catalyst entering regenerator 62 forms a dense, fluidized bed 95 which has a level 96. The temperature of the catalyst bed 95 is 965 F. and it is at a pressure of 200 p.s.i.g. Air is supplied to the bottom of regenerator 62 by means of a line 98 at the rate of 520 pounds per hour. The remainder of the combustion air enters by means of instrument bleed lines (not shown).

As a result of the rejuvenation treatment, the platinum catalyst contains adsorbed oxygen and at least, in part, the platinum has reacted with the oxygen. The rejuvenated catalyst can be returned directly to the reaction zone by reason of the reducing atmosphere therein. However, by passing rejuvenation catalyst directly to the reaction zone there may be a loss of hydrocarbon material by virtue of the reduction reaction with the catalyst. To avoid this adverse efiect, the rejuvenated catalyst is treated with gasiform reducing agent, for example, recycle gas containing hydrogen and normally gaseous hydrocarbons. The reduction treatment can be conducted at a temperature of about 500 to about 1100 F. and for a period of about 5 minutes to 10 hours, more usually, about 15 minutes to about 2 hours. In the drawing, regenerator 62 is separated from reducer 63 by means of a partition 101. The rejuvenated catalyst is Withdrawn from regenerator 62 by means of standpipe 103 which contains a plug valve 104 in the bottom end thereof for the purpose of controlling the rate of catalyst withdrawal. The catalyst entering reducer 63 forms a dense fluidized bed 106 having a level 107. The temperature in the reducer is maintained at 930 F. and at a pressure of 204 p.s.i.g. Recycle gas is introduced into the bottom end of the reducer by means of line 109 at the rate of 288.6 pounds per hour. The reduced catalyst is withdrawn from the reducer by means of transfer line 25 having a bend 111 in the middle portion thereof. The gaseous reaction product is discharged from reducer 63 by means of line 113 which contains valve 64 for controlling pressure therein, and this line is connected to disengaging section 21 of the reaction system.

The recycle gas which is used for stripping in stripper 41,'

stripper 60 and reducer 63 is supplied from line 115. The recycle gas used for stripping in strippers 41 and 60 is divided from line 15 at line 116 and this line is, in turn, connected to lines 48 and 68.

As previously noted, the gaseous reaction product from reducer 63 and the flue gas from stripper 60 are passed to the disengaging zone 55 of the reaction system. By this method, catalyst fines entrained in these effluent streams can be recovered along with the entrained catalyst fines in the reaction product in a single scrubbing operation to be described in more detail hereunder. The total 7 gisetnls materialin disengaging 1 zone: 55 1 contains :en-. trained catalyst-whichlis separated-therefrom to asubstan tia'l extent by 'means of cyclones :120 ands121 *whicht-are: connectedin seri'e'ss- The" separated catalyst is returned to'the' catalyst bed 35 b y:means :of !diplegs 123- and 124.- The 'gas'eousreaction product is discharged-from cyclone lll at'the rate of- 115,354 poundstpert hour, and ithas a molecular 'weight of 26:3; The gaseous reaction product has-a'temperature'of 9305" F; prior to enteringtan indirect heat'exchanger' 126 wherein the temperature is reduced to 648= F.- The tooled-reaction PI'OdLICtiTPaSSGS from ex changer*126':to1a"secondr "exchanger-127 by means of line 128: As a- 'result 'of passingethrough exchanger-127,: the: temperature of thereaetibnsproductis reduced to.420? F. and -thence, it passes from theexchangerr'to a'combina-. tion frtrctionator-scrubbing:ztower: 130i by r means of line 131'. In' the' upper :part of tower 130,? there-is situated fractionating platesfl33; .whereas in the middle portion of the tower there -arelprovided baffles 135 forthe purpose of" scrubbing catalysttfines from the ascending gaseous material. ln' the' bottom part of tower 130, there is a paIti-- tionwhic'h forms section 135-finthebottom of the tower. Theitemperaturexat'the top:of' theitower is 350 F. and theipressure is'517t5 p;s.i.g,-; Onthe'other hand, the temperature in 'the' bottom ;part of the 1 scrubbing section is 375 9 F.'and the pressure sis- 180 p:s.i.g;' The liquid whichcollects-inwell' 140 located inthe-fractionation section of thetower1302is-Withdrawn: by means of line 141 and pump5142at2the rateof 840pounds per hour. The with drawn liquidis transported: by means of line 143ito'the gland" (not :shown)-oi pumpr144r Liquid is withdrawn from section' 130iabove partition :136-by means of line 146, and its is pumped by means of: pump.144 to provide that 4500 pounds per hour are transferred to settling-zone 137 by means of line 148. Th'ezother portion-isitransported :from line -148*:through-':1inec150; cooler 151 and line-152= at .the rat'e"of- 101,000 pounds per..hour, and thence it enters the upperpartzofrhe scrubbing section 1303 I The temperature of the liquid flowing through cooler 151 isv reduced from 375 9 F; to 345 F.- In settling-zone 137, thezfinest'in' the liquid settleitozthe bottom of conical section --154, thus forminguavsupernatant liquid in the uppertpart thereof. The' slurry of catalyst finesisfwithdrawn'fromithebottorn of conical section 154'by means of linerl56; and it:is recycled to=reaction section 205 i The supernatant. 1 liquid is :settling a section 137 is J withdrawn therefrom'vialine 158r-whichcontains a filter 159. This liquid isapolymer having an API':gravity of 32"., and it iswwithdrawn at tthe-rateof '300 b.'p.s.d. Avaporous overhead material is withdrawnfrom the top of tower 130- through line161 at the rateof 134,957 pounds per hour. This overhead 'vaporousmaterial isrcooled in condenser 162,;and': thencepit isipassed to an accumulator 163 by means-ofline 164: The' temperature of the product man.= terialin -accumulator-.163 is 110 F. and it has a-pressure of-.-170 p.s.i.g. The liquidtproduct material in accumulator'-'163--is-' withdrawn'rtherefromsby means of'bottom line -166,-and 24,113 pounds-per hour of'this material'arepassed throughline 167:; By means 0f pump 168; this:- liqnid-is recycled to-the -top:of-.tower 130 through line 17.0w; Theremaining portion of the liquid in line 166'ispassed through another line 171 at the rate of 85,237 pounds-pen hour. Theliquidin line 171 is'combined with thexpolymer in line. 158 and thecombined stream representing the total liquid product is passed to a prodnet recovery system .(not shown) -by means of line 172. The gaseous =product material in accumulator 1631.is withdrawn from the top thereof by =means ofl-line 175: A; portion ofthis-stream; i.e.; 9246 pounds per hour, is yielded throughvlinej-176 as a product of the process. An'- other portion ofithisgaseous producttmaterial is divertedfromqline 7175 to another :linepl78 ,atthe rate of: 16,566 pounds perhour. This'strearn'serves'as:recycle gas, and; as previouslyindicated, it hasa molecular 'weight of 7. 3; recycle-gas enters a 'liquidztrap 180 in: which liquid;

8 is collected and'rdischai'g'ed:fromthe bottbm end thereof by means-20f line 1813 The gaseous-material is discharged from: trap :druni' 'viaan 'overheadSline: 182,1 and thence; it is' pass'ed to" a compresson 184: The compresseduecycle.

1 gas 'is dischargedvfrom the-compressor '184 'by:mean"s of final-35; 'Ihisfrecyclegas'has a temperature @0f' 190F-." and a: pressure'zoff245 p.s.i.-g;. A portion .of-'the-recycle gas passes through line 187 and thence," enters-' coil- 188 of' furnac'e 9awhereintherrecycle gas is heated to aatem perature of 700 F'. Thezheated recycle gasis discharged from coil i188' by means\of line '115i The other-'portiorn of compressed recycle gas is passedfrom line to valved line 190'rwhich'is2 connected to coil 191 int-furnace 9;" This heatedxrecycle' gas is discharged from furnace coil:

' 191at the'rate:of-14g441 pounds per hour at a'tempera-'* ture of=1050 F; via linevllp Having thus "provided'ra-idescription of this invention-- along-with'specific examples thereof, it should be under stood that'no undue limitationsor restrictions are to be imposed'by reason thereof, but that the scope of this in vention is defined by the appended claims.

I claim:

1. A--unitary vessel for'eifectinga chemical reaction in the:presence.-offinely=divided fluidized contact material comprising-in combination a' first fluidized ma tcri'al'contact zone in the bottom of said-vessel, a'p1urality of" adjacently: positioned elongated substantially vertical-passageways disposed in the lower portion-of said vessel above said first contact zone, said passage ways surrounded by a heat exchange medium; an enlargedreaotion-zone positionedabove-and in open-com'-- munication withsaid plurality 'of passageways; said-enlarged 'reaction'zone'of 'suflic'ient sizeto maintain a-de'n'se" fluidized' bedof contact material -in-the lower portion thereof -'in commiinicationwith the-top of i said passage- Waysand a-dilutephase of contact material in the upper portionof said enlarged reaction zone, a strippingchamber positioned abovesaidre'action zone, afirst conduit means extending from th lower portion ofsa'id reaction zone into said stripping zone, a second-con duit means extending from the upper portion of said stripping chamber 'to=the lower portion of said reaction zone, athirdwonduit in open-communication with"the upper portion' of said'stripping chamber and' said-reaction'zone; a fourthconduit means connecting the upper portion of said 'densefiuidizedbed in said reaction'zone with said"firstcontact zone,means for introducing re actants -to said first contact zone, means'for introducing finely' divided conta'ct material to said first'contact zone, means for passing reactants in 'a' dilute suspension of contact materiah from said contact zone' upwardly through said elongated passagewaysinto said dense fluidizedbed; means for removing products of reaction from theupper portion ofsaid reaction zone; means for introducing'stripping' gas to the lower portionof said stripping'zone-and-means for returning stripped'contact material from'said stripping'zoneto said 'first'contact' zone."

2. A unitary vessel'for effecting a chemical reactior'rin the presence of finely divided contact material which comprises, a plurality of elongated'adjacently positioned contact zones in the lower portion of said vessel, a dense fliiidized phase solid contact material reaction zone positioned above a said plurality of elongated contact zones and in opencommunication therewith, a stripping zone positioned above said reaction zone, the upper portion of said strippingrzone being in open communication with the upper portion of said reaction zone, a first substantially vertical conduit extending from the lower portion ofsaid dense fluidized phase in said reaction zone into'said stripping zone, a second substantiallyyertical couduitextending from the upper portion of said densefluidized phasein said reaction zone to :the upper-portion of 'said stripping :zone; a COR! duit connecting the upper portion of said dense fluidized phase in said reaction zone with the bottom of said plurality of elongated contact zones, means for passing a heat exchange medium in indirect heat exchange with said plurality of elongated contact zones, means for withdrawing said heat exchange medium, means for withdrawing contact material from said stripping zone, means for introducing stripping gas to the lower portion of said stripping zc-ne, means for introducing solid contact material to the bottom of said plurality of elongated contact zones and means for introducing reactant to said plurality of contact zones.

3. A vessel for eflecting a chemical reaction in the presence of finely divided solid contact material comprising in combination a mixing zone in the lower portion of said vessel, a plurality of adjacently positioned substantially vertical elongated reaction zones positioned above said mixing zone, said plurality of elongated reaction zones in indirect heat exchange with a heat excange medium, a reaction zone positioned about said plurality of substantially vertical reaction zones of sufficient size to maintain a dense fluidized bed of contact material therein, a settling zone positioned above and of larger cross-sectional area than said dense fluidized bed reaction zone, a stripping zone of smaller cross-sectional area than said dense fluidized bed reaction zone positioned above said settling zone and separated therefrom by baflle means, the upper portion of said stripping zone being in open communication with the upper portion of said settling zone, a first conduit extending from the lower portion of said dense fluidized bed into said stripping zone, a second conduit connecting the upper portion of said dense fluidized bed with the upper portion of said stripping zone, a fourth conduit connecting said dense fiuidized bed with said mixing zone, means for introducing stripping gas to said stripping zone, means for withdrawing stripped contact material from said stripping zone, means for regenerating contact material withdrawn from said stripping zone, means for passing regenerated contact material to said mixing zone, means for introducing a reactant to said mixing zone and means for withdrawing reaction products and stripping gas from the upper portion of said settling zone.

4. A reaction vessel for eflecting a chemical reaction in the presence of finely divided solid contact material which comprises in combination a reactant-solid contact material mixing chamber in the lower portion of said vessel, a plurality of elongated substantially vertical reaction conduits positioned above said mixing chamber, said plurality of elongated reaction conduits in indirect heat exchange with a heat exchange medium, a reaction chamber positioned above said plurality of elongated reaction conduits and in open communication therewith, said reaction chamber of larger diameter than said mixing chamber and of suflicient size to maintain a dense fluidized bed of contact material therein above said plurality of elongated reaction conduits, means for passing reactant from said mixing chamber in a dilute suspension of contact material upwardly through said plurality of elongated reaction conduits into said dense fluidized bed, a stripping chamber positioned above said reaction chamber and separated therefrom by a balfle means, a conduit connecting the lower portion of said dense fluidized bed with said stripping chamber, a second conduit connecting the upper portion of said dense fluidized bed with the upper portion of said stripping chamber, a third conduit connecting the upper portion of said dense fluidized bed with said mixing chamber, means for introducing reactant and finely divided contact material to said mixing chamber, means for introducing stripping gas to said stripping chamber, means for withdrawing stripped contact material from said stripping chamber and means for withdrawing products of reaction and stripping gas from said vessel.

5. A unitary vessel comprising in combination a mix ing chamber, a reaction chamber of larger diameter than said mixing chamber, a stripping chamber of smaller diameter than said reaction chamber, a plurality of adjacently positioned elongated conduits connecting the upper portion of said mixing chamber with the lower portion of said reaction chamber, said elongated conduits surrounded by a heat exchange medium, a first conduit external of said vessel directly connecting said reaction chamber with said mixing chamber, a second conduit internal of said vessel connecting the upper portion of said reaction chamber with the upper portion of said stripping chamber and means for passing a gaseous suspension of finely divided contact material upwardly through said vessel from said mixing chamber to said stripping chamber,

6. An apparatus comprising in combination a first vessel, means for passage of a gaseous suspension of finely divided solid material upwardly through said vessel and through an indirect heat exchanger chamber with a reaction chamber of large cross-sectional area superimposed above said heat exchange chamber and in which a dense fluidized bed of contact material is maintained, a first stripping chamber of reduced cross-sectional area relative to said reaction chamber positioned in the upper portion of said first "cssel and above said reaction chamber, a second substantially vertical cylindrical vessel positoned adjacent to said reaction chamber comprising an upper stripping chamber, a first regeneration chamber, a second regeneration chamber and a bottom reducing chamber, said first regeneration chamber positioned above said second regeneration chamber, a first transfer conduit for the passage of finely divided solid material from the first stripping chamber to said upper stripping chamber, a second transfer conduit for the transfer of finely divided solid material from the upper stripping chamber to the first regeneration chamber, a third transfer conduit for the transfer of finely divided solid material from the first regeneration chamber to the second regeneration chamber, a fourth transfer conduit for the transfer of finely divided solid material from the second regeneration chamber to the reducing chamber, and a. fifth transfer conduit for the transfer of finely divided solid material from the reducing chamber to said indirect heat exchange chamber and means for passing a gaseous material upwardly and sequentially through at least two of said chambers in said second vessel.

7. An unitary vessel comprising in combination a mixing chamber positioned in the lower portion of said vessel, a reaction chamber positioned in the intermediate portion of said vessel, a plurality of open end elongated conduits connecting the upper portion of said mixing chamber with the lower portion of said reaction chamber, said reaction chamber being of larger dimensions than said mixing chamber and of suflicient size to maintain a dense fluidized bed of finely divided solid contact material therein, an elongated substantially vertical stripping chamber superimposed above said reaction chamber and of smaller diameter than said reaction chamber, conduit means for passing a reactant to said mixing chamber, conduit means for passing finely divided solid contact material to said mixing chamber, means for passing reactant in a dilute suspension of finely divided contact material from said mixing chamber upwardly through said plurality of elongated conduits in indirect heat exchange with a heat exchange medium into said dense fluidized bed in said reaction chamber, conduit means for withdrawing products of reaction from the upper portion of said reaction chamber, means for maintaining a dense fluidized bed of contact material in the lower portion of said stripping chamber, means for stripping contact material in said stripping chamber, a first conduit connecting the dense fluidized bed of contact material in said reaction chamber and said stripping chamber, a second conduit connecting the dense fluidized bed in said reaction chamber with the supper portion of P said #stripping ichambei above' the densefluidized':hed--therein, a:

thirdmonduit-connebting the upper portion of said re'ac tion chamber with the 'upper" portion *of said' strippingchamber, a "fourth conduit connecting themixing chamher with the-:upp'er portion of 'saidde'nse fluidiZedbed-in said'ireaction chamber and conduit means for Withdraw ingstripped "contact material *from :said stripping chamber.

85 An apparatus comprising-sin"combinationa first elongated 'substantially'vertical vessel, said first vessel containing a 'lower 'mixingchamber; anindirect heat exchangechamberpositioned above said mixing chamber, a reaction chamber positioned'above said: indirect-heat exchange chamber, a stripping chamber 'positio'ned'above said reaction chamber and means for passingfinely di-' vided contact niaterial 'fromsaid "mixing-chamber upwardlythrough said indirect 'heat exchange chamber and said reaction chamber into said' stripping chamber, a

second elongated substantially vertical vessel positioried' adjacennto said'first' vessel, said second vessel divided intoa-plurality of'superimposeclcontact chambers, means forrniaintaining aidense fluidized bedof'cont'act material in-eachtofsaidcontact chambers, means for passing con-' tact 'material downwardly and sequentially through 'each of said chambers insaid second vessel, means for passing a 'gaseous:material'upwardly and sequentially through at" least two of said plurality of contact chambers, means for'passing -a-gaseous material from the upper portion of al? least one of said contact chambers tothe upper portion of said 'reaction chamber, means for passing,

finely'div'id'ed contact material from said stripping chambertotheupper portion of said second vessel and means for passing contact material from the lower portion of said second' vesselto said mixing chamber. 

1. A UNITARY FOR EFFECTING A CHEMICAL REACTION IN THE PRESENCE OF FINELY DIVIDED FLUIDIZED CONTACT MATERIAL COMPRISING IN COMBINATION A FIRST FLUIDIZED MATERIAL CONTACT ZONE IN THE BOTTOM OF SAID VESSEL, A PLURALITY OF ADJACENTLY POSITIONED ELONGATED SUBSTANTIALLY VERTICAL PASSAGEWAYS DISPOSED IN THE LOWER PORTION OF SAID VESSEL ABOVE SAID FIRST CONTACT ZONE, SAID PASSAGEWAYS SURROUNDED BY A HEAT EXCHANGE MEDIUM, AN ENLARGED REACTION ZONE POSITIONED ABOVE AND IN OPEN COMMUNICATION WITH SAID PLURALITY OF PASSAGEWAYS, SAID ENLARGED REACTION ZONE OF SUFFICIENT SIZE TO MAINTAIN A DENSE FLUIDIZED BED OF CONTACT MATERIAL IN THE LOWER PORTION THEREOF IN COMMUNICATION WITH THE TOP OF SAID PASSAGEWAYS AND A DILUTE PHASE OF CONTACT MATERIAL IN THE UPPER PORTION OF SAID ENLARGED REACTION ZONE, A STRIPPING CHAMBER POSITIONED ABOVE SAID REACTION ZONE, A FIRST CONDUIT MEANS EXTENDING FROM THE LOWER PORTION OF SAID REACTION ZONE INTO SAID STRIPPING ZONE, A SECOND CONDUIT MEANS EXTENDING FROM THE UPPER PORTION OF SAID STRIPPING CHAMBER TO THE LOWER PORTION OF SAID REACTION ZONE, A THIRD CONDUIT IN OPEN COMMUNICATION WITH THE UPPER PORTION OF SAID STRIPPING CHAMBER AND SAID REACTION ZONE, A FOURTH CONDUIT MEANS CONNECTING THE UPPER PORTION OF SAID DENSE FLUIDIZED BED IN SAID REACTION ZONE WITH SAID FIRST CONTACT ZONE, MEANS FOR INTRODUCING REACTANTS TO SAID FIRST CONTACT ZONE , MEANS FOR INTRODUCING FINELY DIVIDED CONTACT MATERIAL TO SAID FIRST CONTACT ZONE, MEANS FOR PASSING REACTANTS IN A DILUTE SUSPENSION OF CONTACT MATERIAL FROM SAID CONTACT ZONE UPWARDLY THROUGH SAID ELONGATED PASSAGEWAYS INTO SAID DENSE FLUIDIZED BED, MEANS FOR REMOVING PRODUCTS OF REACTION FROM THE UPPER PORTION OF SAID REACTION ZONE, MEANS FOR INTRODUCING STRIPPING GAS TO THE LOWER PORTION OF SAID STRIPPING ZONE AND MEANS FOR RETURNING STRIPPED CONTACT MATERIAL FROM SAID STRIPPING ZONE TO SAID FIRST CONTACT ZONE. 